pasmado15

There must be a reason for the lack of popping as before I installed a 160 versus 180 degree WT.

With the 180, I could listen to popcorn while running 75 MPH at 2k RPM then releasing the gas pedal --- what a nice sound it was... THe temp then was usually 200.

Now for the last 1K miles with the 160 WT, I have no such popcorn. The temp is about 170.

On the plus side - I now get 4 more miles per gallon --- up to 31.

Any ideas as to why?

No codes, and all other parameters pass the scanner tests.

Wild1

That popping sound is typically raw fuel. If there is a misfire, typically ignition, it will not spark the plug and send raw fuel down your hot exhaust pipes igniting it on decel.

Not sure why a thermostat would affect the fuel mixture that drastically. The cooler temps should make the fuel richer. I'd pop the hood at night under TOTAL darkness and start the engine. Look for any faint blue sparks around the plugs or wires. You could have an intermittant.

pasmado15

Just came back from upstate NY... I just checked for faint blue sparks to no avail.

I'll wait for summer to decide if I'll change back to the 180 WT.

I'll have to decide what is best: better performance or better sound effects.